You say Myanmar, I say ... oy vey
Is it Myanmar -- the choice of the ruling junta -- or Burma, the choice of the U.S. government, which never recognized the junta as a legitimate government?
It gets messy -- and complicated. See the debate at the American Copy Editors Society discussion board. Strong views all around.
Language Log also weighs in. The AP favors Myanmar. (Search for Burma).
John McIntyre, who is in charge of desks at the Baltimore Sun, puts it well:
It's hard enough for the copy desk to make decisions about what will be intelligible to the audience without our having to rule on the legitimacy of governments and the legacies of colonialism.